compute shaders and uniform blocks

Hi,

Have just started working on compute shaders.
I have a uniform block in a compute shader and I am trying to get the uniform block index in my application , but it is always returning me index as -1. Whereas for normal uniforms (without blocks) it is returning proper location values (+ve values) . I am working on OPENGL 4.3 with GLSL 430 on Nvidia quadro 600.